US842285A - Block-signaling system for railways. - Google Patents

Description

N0. 842-,285- PATENTED JAN. 29; 1907.

A. J. WILSON. I I

BLOCK SIGNAHNG SYSTEM FOR RAILWAYS.

APPLIOATION FILED AUG.21,1906.

I I 742 ATTORNEY- UNITED .sTA r s PATENT OEEI E.

ADOXIRAM J. WILSON, OF WESTFIELD, NEW JERSEY, 'i'issievo'n TO THE HALL SIGNAL COMPANY, A CORPORATION OF MAINE.

BLOCK-SIGNALING SYSTEM FOR RAILWAYS.

. To all whom it may concern:

Be it known that I, ADONIRAM J. W lson,

a citizen ol' the United States, and a resident of Westlield, in the county of Union, State of New' lersey, have invented certain new and Isa specification.

This invention relates generally to blocksignaling. systems, but more particularly to' block-signaling systems for electric radways. The invention seeks to provide a system Whichis reliable under all conditions. highly eflicientin operation, and which reduces the maintenance factor to a minimum.

' A feature of the present invention is its capability of employing-the same source of electric energy as that employed forthe propulsi'on of trains also for the e'nerqiz'ation of its various signal and track circ nts, in which case a continuous return-rail extending Jhroughout. all the blocks and the trolleywireor third rail are jointly employed as. power-mains. for the signal-circuits aswell as for the trains.

In carrying out the invention one or more trackscontrolleii electromagnetic devices are employed at each protected block, and it s preferred that one of these devices be difierentially WO1111 (1 and be controlled jointly b the .opposite rails oi the block, The system contemplates the protection of a plurality ofblocks by means of a home and a distant signal near the entrance to a block and by rerious interdependent and local signai-cir- I and distant signas for the block 3 1, and 19 cuits. The signals are shown as of the normal'dangertype, and a eculiar feature 01" tne system is their depen. once-upon an ap 1n-.

preaching train-before -giving a .sal'ety dlcatlon and then. only incese ofa clearl block ahead.- The control of the'signal-eir cuits from one block to anotner, together with the means employed toe-fleet this control, is

' aieature'of the invention.

rnoth er obj ect is to provido sultahlelocal means. Whn'h'wdlefiect; a considerable economy in line-wire betw 'een blocks.

A system is illustrated which both home I and distant signals ar' -properlv controlled through the medium of a'single through-wire between blocks;

- An embedimem; o'l't'he invention is Show]; in the following drawing, forming ,part of the specification, and in, which the figure I Specification of Letters Patent. Application filed August 21,190 6- Serial No. 331,426.

. e'ast-bound trackQ Referring now more particularly to the, drawing, the figure illustratesa portion each.

' netic device associated I lay 22,w'hile 26'and 27 each designates asimil ar Patented Jan. 29, 1907."

shows the signaling system applied to an of a west and an east bound track. the svs- 'tem being snown in its ap lication to the 13 divided mto .V&I101IS lJlO('lS,'aS shown. AOIll7lIlllO1.1S recast-bound track. '1 he trac turnsrail 1 extends throughout alt the blocks of tneeast-bound track.- Tne various blocks are determined by the insulated rail-sections 2 4 5, &c. 'lhus each block comprises a portion of a continuous return-rail and an 1nsulated rail-section' The first block will be designated by 2 l, the second or nextsucceeding hlock'by 3 1, the third by 4 1, and thefourth by 5 1. the West-bound track are designated by 7 6,

Corresponding blocks for 8 6, 9 6, and, 10 6.. The West-bound track. might be provided \Vll-h the svstem, if desired,

tively. The. adjacentend of the'neighbor- 1 ing rail-section is also bridged acrossto the continuous return-rail l as shown, by a track- .r'elay-l-l for sectlon 2,15 for sections, and

16 ,tor section 4. v a

17 and 18, res actively, designate home and 20 design-ate'home and distant signals,

respectively, for the block a 1.

All the signals, circuits, and apparatus are shown'in their normal positions and normalconditions, and at least. onecomplete circuit of each varietv embodied in the system is illustrated and will be described.

21, 22, and 23 each designates an' electromagnetic device, andparticularly a diflerential magnetic device or relay associated, re-I lco slpectively, Withthe blocks 2 -1, 3 '1, and 4 1.

hesmdevices. are included, as will be de-- scribed, in the track-circuits.

" 24- and 25 each desi nates an electromagwith differential reelectromagnetic deviceassociated with (litferential relay 23. similar installation is return-rail 1.

"return rail 1.

ofcourse provided in connection with differential relay 21, although this is not illustrated in detail to obviate unnecessary repetition.

28 is a source of electric energy, preferably that for supplying motive power to the trains.

return-rails 1 and 6 by third rail or trolley -wir'e It is connected to the wire 29 and to the 30 by wire 31.

Each protected block has associated therewith a normally energized track-circuit coirprising two branches, each extending through one of the two oppositely-wound coils of the differential relays 21, 22, and 23, respectively.

The branched track-circuit for block 31 is as follows: third rail 30, potential reducing resistance 32, Wire 33 to point 34, then branching, first through coil 35, Wire 36, electromagnetic device 25, wire 37, to returnrail 1; second through opposing-coil 38, wire 39, electromagnetic device 24, wire 40, "insulated rail-section 3, thence through track resistance 11 and track-relay in parallel to A similar track-circuit for block 4 1 may be traced as follows: third rail 30, resistance 41,v wire 42 topoint 43, then branching, first through coil 44, wire 45. electromagnetic device 27, wire 46, to'returnrail 1; second through opposing coil '47, wire 48, electromagnetic device 26, wire 49, insulated rail-section 4, then through track resistance 12 and track-relay 16 in parallel to When tracing all circuits, third rail and return-rail 1 are regardedas the'opposite terminals of the source of electric energy, since for all practical purposes they are such. 'Each of these branched.

track-circuits is normally energized, and each of the coils of theelectromagnetic devices included therein normally have a magnetizing effect. The branch. through coil 38 has included therein the resistance of track resist-' ance 11 and track-relay 15, which is not included in the branch through coil 35. Therefore the normal current through this branch is less than that through coil 35. The magnetizing effect of coil 35 therefore overbalances that of the coil 38 in normal condition, and the combined coils of the differen- .tial device have a normal joint magnetizing effect or normal operative effect. However, if a train bridges insulated rail-section 3 to return-rail 1, track resistance 11 and track magnet 15 are shunted out, and the current through coil 38 is made equal to that through v e coil 35, the joint n'iagnetizing eifectof t two coilsbeing destroyed and the difierential. device having an inoperative effect. The branched track-circuit through difi'erential relay 23, as illustrated, has functions similar to those describedin connection with differential relay 22. Obviously the branched trackcircuit through differential relay 21 must also be similar. g

98 is a shunting-relay for block3 1, and 99 is a shunting-relay for block 4 1. These re lays are normally deenergized, and each operates a local circuit upon actuation from a preceding block, as will be described.

The first holding-circuit of the system and, namely, that for home signal 17 may be traced as follows: third rail 30, resistance 32,

wire 53, contact 54, armature 55, wire 56, contact 57, armature58, wire59, signal 17, wire 61, circuit-closer 102, through-wire 62, wire 63, contact 64, armature 65, wires 66 and 67, to return-rail 1. This circuit is normally'open, as shown at 102 and 64.

The signal-circuit for home signal 17 may be traced as follows: third rail 30, resistance 32, wires 33 and 50, armature '51, contact 52, wire 53, contact 54, armature 55, wire 56, contact 57, armature 58, wire 59, signal 17, wires 61 and 68, contact 69, armature 70, compensating resistance 71, wire 40, insulated rail-section 3,track resistance 11, and trackrelay 15 in parallel toreturn-rail 1. This circuit is normally open, as shown at 69. The next succeeding holding-circuit and, namely, the circuit for home signal 19 may be" traced as follows: third rail 30, resistance 41, wire 42, wire 72,-armature 73, contact 74,

contact 79, armature 80,, wire 81, signal 19, wire 82, circuit-closer 93, through-wire 83, wire 94, contact 95, armature 96, wires 97 and 37, to return-rail 1-. This circuit is normally open, as-shown at 93 and 95. The next succeeding signal-circuit and, namely, that for the home signal 19 may be traced 'as follows:-third rail 30, resistance 41, wires 42 and 72, armature ,73, contact 74, wire 75, contact 76, armature 77, wire 78, contact 79, armature 80, wire 81, signal 19, Wires 82 and 89, Contact 90, armature91, compensating resistance 92, .wire 49, insulated rail-section 4, track resistance 12, and track-relay 16 in parallel to return-rail 1. This circuit is nor- 'mally 0 en, as shown at 90. 1?

' The rst clearing-circuit completelyfshown "in the drawing and for home signal ,19' of block 4 1 may be traced as follows: third rail 30, resistance'41,, wires 42 and 72, armature 73, contact 74,-wire 75, contact 76, armature signal 19, ,wire, 82,. through-wire 83, armature 84 contact 85, circuit-closer 86, Wire 8,7, distant signal 18, wire 88ft'o return-rail 1. This circuit is normally open, as shown at and 86. A simila'r clearing circuit for home shown complete so, far as block 3 1 is concerned, and may be traced as follows: third tiire 51 oontact 52, wire 53, contact 54, ar-

wire 59, home signal 17, wire61, shuntingrelay 98, through-wire 62 toimechanism m i the preceding block similar to that described wire-33, Wire 50, armature 51, contact 52,.

Wire 75, contact 76, armature 77, wire 78,

77, wire 78, contact 79, armature 80, wire 81', shuntingrelay' 99,

rail 30, resistance 32, wires 33 and 50, arma-- mature 55, wire 56,- contact 57, armature too signal .17 is in connection with through-Win83. A portion of a third similar clearing-circuit enters block 4 1 on through-wire 100, as shown, and a portion of a fourth clearing-circuit is des1g-' nated by wire 101.

The signalcirciiit for I distant signal 18' may be traced as follows: third rail 30, re-

sistance 41, wires 42 and 72, armature 73,

contact 74, Wire 75, contact 76, armature 77, wire 78, contact 79, armature 80, wire 81, home si al 19, wire 82, circuit-closer 93, through-wire 83, armature 84, contact 85, circuit closer 86, wire 87, distant signal 18, wire 88' to return-rail 1. This circuit is nor-'. mally open, as shown at circuit-closer 93,

- contact 85, and circuitcloser 86.

A ortion of the signal-circuit for distant signal 20 may be traced as follows: from block 5 1, over throu h-wire 100, armature 103, contact 104, circuit-closer 105, Wire 106, distant signal 20,.wire 107 to return-rail 1. This circuit is similar to the signal-circuit for distant signal 18, previously described and shown complete in the drawings- Circuit-closers 86 and 102 are normally trated as leading to the signal-blades, it is to be understood that this is merely a diagrammatic indication and that the circuits do not necessarily lead directly through the motor for operating a signal, but ma include any signal device, such as a clutc -magnet, releasingmagne't, or many other similar devices, all well known in the art.

The operation'of the system in response to a train advancing in-an easterly direction along. the east-bound track is as follows: Home signal 17 has been cleared by the advancing train in a manner similar to the subsequent clearing of home signal 19, which will presently be described. Signal 17 now at safety has closed circuit-closers 86 and 102. As the train advances into block 2 1, the differential relay 2] loses its normal operative effect in the same manner in which differential relay '22 loses its normal operative effect, as will presentlybe described Circuit-controlling armature or. circuit-breaker will be released, closing holding-circuit for home signal 17 at 6 c to holdsaid signal at safety. The train also shunts out the track-relay 14 in a manner similar to the subsequent shunting out of tra ck relay 15, presently to be described. Armature 84 is released to make contact with 85 and close the clearing-circuit for home signal 19 of the sec ond block succeeding .block 2 1. Current now traverses shunting-relay 99, which is provided with a comparatively large winding and possesses a considerable resistance, so as to requlre a comparatively small actuatmgcurrent. This relay is now energized and at-' tracts its controlling-armature 91, closing the signal-circuit for home signal 19, previously traced at 90. p The closing or this armatu re 91 provides a short return for the circuit of home signal 19 to return-rail 1 and in: c'reasesthe current for this signal sufficiently tothrow home signal 19 to safety. Signal 19 on going to safety closes circuit-closers and 93. The closing of circuit-closer 93 shunts out shunting-relay 99, thereby deen ergizing the same and sending back a strong current over through-Wire 83 to distant signal 18, which then goes'to safety in advance of the train. As the train advances into block 3 1- its wheelsand axles bridge insulated rail-section 3 across to return-rail 1. Track resistance 11 and track-relay. 15 are therefore shunted out. Both branches of-the branched track-circuit for block 3 1 are now caused to have each the same resistanceand the current through them is equalized. The

two opposmgcoils 35 and 38 of differential relay 22 being equal and opposite now losetheir joint magnetizing or operative efiect and release both; the controlling-armatures 55 and96. These armatures may be termed respectively, a "circuit-closer and a circuit-breaker. 55 opens the holding-circuit for home signal 17- at54. Signal 17 thereupon goes to danger, opening circuit-closer 86, which opens the previously-closed circuit fordistant signal 18 and causes said distant signal 18 to go to danger. Both signals 17 and 18 are now at danger as the train enters block 3 v1 and will protect the rear of the train.

for home si nal 19, so that before the signalc rcult for ome signal 19, extending over through-wire 83 through circuit-closer 86, is

broken at 86 this ho ding circuit will be closed, so that the home signal will still be held at safety in advance of the train. As

the train leaves block 2 1 difi'erential relay 21' and track-relay 14 regain their normal condition, and the circuit over through-wire 83 is opened at a second point 85. shunting out of track-relay 15, previously re ferred to, denergizes the same to release the armature 103, making contact witl1'104 and home signal and afterward clearing distant s gnal 20 in thesame manner that distant signal 18 was cleared. As the train'enters I The released armature 96 makes contact with 95 to close the holding-circuit lIO The

closing a clearing-circuit forthe. succeeding block 4 1 it bridges insulated rail-section 4 to return-rail 1 to destroy the normal operas tive effect of differential relay23 in the same wayas was described in connection with differentlal relay 22. The signal-circuit. for.

izs

home signal 19 isthereupon broken a't'76 upon the retraction of armature 77, and.

A complete operation both for clearing and going to danger of home signal 19 an distant signal 18 has now been described, and it is to be understood that this operation may indefinitely be repeated for other similar signals. The description has been for clear blocks ahead of the advancing train.

If the block 4 1 is occupied by a train as an east-bound train advances into block 2 1, distant signal 18 cannot befcleared. Home signal 17 has been cleared as described above.

Circuit-closer 86 has been closed, and arma- .ture 84 is in contact with 85, but the clear ing-circuit for home signal 19 is open at 7 6,

since the train in block 4 1 has destroyed the normal operative efiect of differential relay 23, so that this relay has released its armature 77. Home signal 19 m'ust,therefore,'

remain at danger, since-the shunting-relay 99 cannot be actuated, and also no cur rent can. be sent back over through-wire 83 to clear distant signal 18. Thus signal 17 is at l safety and distant signal 18 is at danger, the two signals giving a combined indication of caution. As the train ad vanccs into block 3 1 home signal 17 is thrown to danger to protect its rear, the same as previously described. This train can advance no farther, since the train ahead in block4 1 is holding home signal 19 at danger' and also distant signal 20 at danger,

- since the circuit for distant signal 20 is held open-at'105. In a similar manner it the block 3 1 is occupied by a train an advancing train will fail to clear home signal 17, since the train in'block 3 1 has-destroyed the normal operative effect of differential relay 22, breaking the clearing-circuit for ,home sig.- 'nal17at54. y

A'train held in block ,3 1 by the danger indication of signals 19 and 20 due to a train occupying block 4' 1 willbeallowedto pass on into the next block as soon as the train in that block departs. The operation-in that instance is .as' follows; The train leaving block 4 1 restores the normaloperative effect of diflerential relay 23, attracting'armature 77, against contact 76, The train waiting in blbck 1 hasreleased armature 96,'Wl1i0h has previously-been described as completing the holding-circuit. In-this instance thefholdbig-circuit acts a's'a clearing-circuit for home signal 19',since there is no train back in block 2' 1 to denergize track-relay 14 and drop armature 84.- The shunting-relay 99' is energized to attract its armature 91 and clear home signal 19, as previously described,

Circuit-closer 105 is closed, track-relay 'is denergized, so that armature 103 is in'contact with 104, with the result that distant signal is ready to be thrown to "safety as soon as theblocking-train ahead has left block 5 1." In any event the train in block 3 l'may advance into block'4 1. 4 Each branch of the branchedtrack-circuits described may be provided, as shown, with I an electromagnetic device, such as 24, 25, 26, 27 and 108. Each of these devices is normally ener ized and holds attracted an armature inclucfed in-the'signal-circuits. All the armaturesassociated with all of the electro.

magnetic" devices are arranged to be re-' tracted upon the denergization of their associated elei'ztromagnetic devices; The purpose of the additional'devices 24, 25, 26,

27 and 108 is to break the signal-circuits at a block if a branch of the tracl'r-cir'ouit extending through one of these devices should The signals accidentally become broken. all have 'a bias 'to danger, so that any cause a dangerindication of the signal or signals affected; I I

From the above description it is obvious thathome signal 19 is controlled by all the electromagnetic devices of the associated break in the various 'signalcircuitswill block-namely, 23, 26, 27, and 99+also by of the preceding block and also by the electromagnetic device or track-relay 14 of a second precedin block. The distant signal 18 is controllediy the electromagnetic devices the electromagnetic devices 22, 24, and 25 23, 26, 27, and 99and bythe homesignalf- 19 through=the medium of circuit-closer 93 of the succeeding block, also by the electromagnetic devices 22, 24, and 25 and by the home signal 17 through the medium of circuit-closer 86 of the associated block and also by the electromagnetic device or trackrelay 14 of the preceding block The other signals are similarly controlled. -.Furthermore,'the' control. of distant signal 18 extends to a portion of the trackin advance of distant signal 20 and therefore overlapsxsig nal 20 in its control.-

, It should be noted that theprovision of the relays 98 and 99 makes it possible fora single through-wire betweenblocks to'clear the signal of one block and also of a preceding block, while each of these signals is subject toa control dependent upon the oo'ndition of the associated block; v

What has been shown and described is cohsidered to be illustrative of a preferred embodiment' of the invention, although various changes indetails are Well Within the scope thereof.

y, y The particular novel features 'ofthe irivening windings, branch; each branch including the rails of a' 1 ;1. In ablock-signaling system,-the combination: of a circuit having two multiple branches; a magnetic device with two opposone associated with each [separate track side; said branches having a device W J said ralls;

normal'o 'ch is changed by train brid ing ger; and'local means operable b an approaching car in a second precedmg block to throw said signal to safety when; said. branches'have their normal operative effect.

2. In a block-signaling system for rail- Ways, the combination withthe block of a circuit having two multiple branches; a mag netic device with two opposing windings, one winding in each branch; each branch including the rails of a separate track side; said branches having a normal operative efiect .u on said magnetic device; a train in the b ock being capable of changing said normal operative effect of said branches; a signal associated With said block; and means associated with a pre'ceding'block and o erable by a car in that block to control sai signal when said branches have their normal operative effect, anda track-relay in a second priced'ing block also for controlling the signa 3-. In an electric block-signaling sy'stenna plurality of blocks; a train-controlled elec' tromagnetic device; for each block normally holding a circuitecloser closed and a circuitbreaker open; a home and a distant signal for each block; a track-relay for each block; a home-signal circuit," a distant signal cirwit; a shunting-relay for said circuits; said home-signal circuit being controlled by the electromagnetic device of the block associated with the home signal, and'bv that of thepreceding block and also by the trackrelay of the second preceding block; saiddistaut-signal circuit being controlled by the electromagnetic devicefand by the shuntingrelay of the succeeding block and by the home signal of the associated block.

4. In an electricblock-signaling system; a pluralityof blocks; a train-controlled electromagnetic device for each block; a home and a distant signal for each block; a trackrelay for each block; a home-signal circuit; a distant-signal circuit; a shunting-rela for said circuits; said home-signal circuit being controlled by theelectr'omagnetic device of the block associated with-thehome signal, and-by that of the preceding'blockand also b the track-relay of the second preceding bIbck;' .saiddistant-signal circuit being c-onr trolledby the electromagneticdevice and b the shunting-relay of the succeeding :bloc

erative eflect upon said magnetica signal normally indicating an--' and by the home signal and by the electro magnetic device both of the. associated block. f

5. In an electric block-signaling system; a plurality of blocks; a train-controlled electromagnetic device for each block; a home and a distantsignal for each block; a track relay for each block; a home-signal circuit; a d1stant signal circuit; a shunting-relay for said circuits; said home-signal circuit'being controlled by the electromagnetic device of the block associatedwith the home signal and by that of the preceding block and also gy the track-relay of the second preceding ck; said distant-signal circuit being controlled by the electromagnetic device and bv the shunting-relay. of the succeeding block and by the home signal of the associated block; a'portion of the distant-signal circuit of one block operating as. clearing-circuit for the home signal circuit of the succeeding block through the medium of the shuntingrelay of said succeeding block so as to necessitate the use of only one through-wire between blocks.

6. In. an electric block-signaling system; a, plurality of blocks; a train-controlled elec' tromagnetic device for each block; a" home and a distant signal for each block; a trackrelay for each block; a home-signal circuit; a distant-signal circuit; a shunting-relay for said circuits; said home-signal circuit being controlled by the block associated with thehome signal, by that of the preceding block and also by the track-relay of the second preceding block; said distant-signal circuit being controlled by the electromagnetic device and bythe shunting-relay both of the block in advance, and by the homesignal and by the electromagnetic device of the associated block; a portion of the distant-signal circuit of one block operating as a clearing-circuit for the homethe electromagnetic device of signal circuit of the succeeding block through the medium of the shunting-relay of said succeeding block so as to necessitate the'use of only one through-wire between blocks.

7. In a 'block signaling system, a plurality of blocks; a distant signal for one block; a

home signal for a distant or succeeding block; a track-controlled device forsaidsucceeding block; an actuating device preceding sai distant signal; a shunting-relay for said succeeding block; a clearing-circuit for said home signal, including said. shunting-relay a signal-circuit for said distantfsig'nal; both of. said circuitsemploying wire betweedsaid block and said succeeding block; both of said circuits being controlled by said actuating device and said -track-con'- trolledldevicefor the said succeeding block;

and a signal-circuit for saidhome signal controlled by said shunting-relay.

but a Single.th1ough-' 1 f 8.. In a block-signaling system; a plurality of blocks, each comprisinga portion of a continuous return-rail and an insulated railsection; a source of electric energy; a differential relay with each of its two opposing windings connected between said source of energy and a separate rail of the block so that said windings have a combined inductive effect when the block is clear and no combined inductive effect when the block is occupied by a train; a track-relay and a shunting-relay for each block; a single through-wire-controlling circuit for the home signal of one block and for the distantsignal of the preceding block said controllingcircuitbeing controlled by said.

relays.

9. In a block-signaling system; three blocks, each block comprising a portion of a continuous return-rail and an insulated railsection; a source of electric energy; a branched track-circuit, each branch connecting an opposite rail of each of said blocks with the source of electric energy; one coil of a differential relay included in each of said branches; a track-relay at the first block; a shunting-relay at the third block; a home and a distant signal at the second block; a home signal at the third block; a circuit for the home signal of the second block andcontrolled by the differential relay of the first block and by the differential relay of the second block including the shunting-relay of the third block and controlled by the track-relay at the first block.

10. In a block-signaling system; three blocks, each block comprising a portion of a continuous return-rail .and an insulated railsection; a 'source of electric energy; a branched track circuit, each branch connecting an opposite rail of one of said blocks with the source of electric energy; a separate coil of a differential relay included in each of said branches; a track-relay at the first block; a

shunting-relay at the third block; a home and a distant signal at the second block; a home signal at the third block; a circuit for the home signal of the second block and controlled by the differential relay of the first block and by the differential relay of thesec- 0nd block; a clearing-circuitfor the home signal of the third blockand the distant signal of the block, the second block includin the shunting-relay of the third and controlle by the track-relay at the first block; a local circuit for the home signal at the third block; said shunt ng-relay operating to increase the current strength first through said local circuit for the home signal at the thirdblock and then after said home signal is thrown, through a circuit for the distant signal of the second block.

11. In a block-signaling system; a plurality of blocks; a signal at each of'two separate blocks; a shunting-relay associated with one of said signals; a clearing-circuit forboth of said signals including said shunting-relay and a source of electric energy; means for closing said circuit; said shunting-relay operating to increase the current strength first for one signal and then, after said signal has been thrown, for the other signal.

12. In a block-signaling system a block comprising a portion of a continuous returnrail and an insulated rail-section a branched track-circuit, each branch included a separate track sideof said block; a separate coil of a differential relay including in each of said branches; a signal for said block; a local circuit for said signal controlled by said differential relay; a clearing-circuit controlled by a track device preceding said block and in parallel with a portion of said local signalcircuit; and a shunting-relay for said local circuit and included in said clearin '-circuit to increase the current in said loca circuit,

when said clearing-circuit is energized.

. 13. In a block-signaling system, a block comprising a portion of a continuous returnrail and an insulated rail-section; .a track resistance connected between said insulated rail-section and said return-rail; a branched track-circuit normally energized; branch including a separate track side of said block; a separate coil of a differential.

relay included in each'of said branches; a signal for said block; a local circuit for said signal controlled by said diflerential relay; a cle'aringcircuit controlled by a track device each preceding said block and in parallel with a portion of said local signal-circuit; and a shunting-relay for said local circuit and in cluded in said clearing-circuit-to increase the current in said local circuit when said clearing-circuit is energ zed.

14. In a block-signaling system, a blockcomprisinga portion of a continuous returnra1l and an insulated rail-section; a track resistance connected between said insulated' rail-section and said return-rail; a branched energized, each IIO of said branches; a signal for said block; a

parallel with a portion of said local si nalcircuit; and -a shunting-relay for said ocal circuit and included in said clearin '-circuit to increase the current in said loca circuit when said clearing-circuit is energized.

15. In a block-signaling system, a Plurality of blocks; each comprising a portion of a continuous return-rail; and an insulated railsection; a branched --track,- circuit, each branch including a" separate track side of a block; a separate coil of a differential relay included in each of'said 'branches; a'signal for a block; a circuitgfor-said signal con-' trolled by the differential'relay of the associated block; a signal for a preceding block a circuit for said latter signal controlled b the differential relay of said preceding bloc and by a portion of the track'succeeding said firstementioned signal so as tooverlap the same; y y 16. In a block-signaling system, a plurality of blocks, each comprising aportion of a continuous return-rail and an insulated rail-'- section; "a branched track.- circuit, each branch including a separate track side of a block ;a separate coil of a differential relay included in each of said branches; a. signal fora block; a circuit for saidsignal concircuit for said latter signal con a portion of the preceding track, and by. a a portion of the track succeeding saidfirstmentioned signal'so asto overlap the same. In testimony whereof I have signedmy name to this specification in the presence of two subscribing witnesses.

i ADONIRAM J. WILSON.

Witnesses:

I MAY V. MOPIKE,

LEONARD DAY.

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